This invention relates generally to a torque transfer device for vehicles with an automatic transmission and more particularly, to a torque transfer device for vehicles having the option of a two or a four wheel drive. Four wheel drive vehicles are becoming more popular in both large and small vehicles. These vehicles generally provide for the option of either two or four wheel drive. However, the torque transfer devices associated with these vehicles are complex, do not operate smoothly, and component wear is high.
What is needed is a torque transfer device for a four wheel drive vehicle which is simple in construction, smooth in operation and has a long operating life. The ability to shift between two and four wheel drive and to reduce speed while the vehicle is in motion is also desirable.